Microsoft said it has fixed a security bug in Internet Explorer that hackers exploited to attack computers.

Although the permanent repair to Internet Explorer browser will be released on Friday, on Wednesday Microsoft published a "Fixit" - one of its automated configuration tools - that blocks the known exploits. The Fixit has been posted in a document on Microsoft's website.

The attacks prompted the German government and security experts to urge people to temporarily stop using the browser.

Network security firm AlienVault said on Tuesday that it had discovered three other servers that hosted malicious websites that exploited the Internet Explorer flaw.